Wireless communication networks that allocate communication resources, such as time or frequency, require a scheduler to select data to be transmitted. When multiple users are vying for these resources, the scheduler must analyze the incoming data and determine the data having the highest priority for transmission. Priority has traditionally been based on maximizing overall system throughput or maintaining a certain Quality of Service (QoS) level to ensure that data is transmitted in a timely fashion. When maximizing throughput, users having better channel conditions are favored over those with worse channel conditions. Thus, the users with the less favorable channel conditions are always given lower priority. As a result, those users with poor channel conditions are prone to lower QoS levels. In contrast, trying to maintain certain QoS levels often leads to unnecessarily low system throughput.
Many schedulers prioritize packets based solely on carrier-to-interference ratios (CIRs) derived from information fed back from the mobile terminals. Such schedulers maximize throughput without regard to fairness or minimum throughput requirements and typically schedule delivery for users that are closest to the base station. Schedulers attempting to provide some degree of fairness use rudimentary scheduling criteria, resulting in poor system throughput. There are also many problems with existing schedulers in terms of supporting multi-media wireless-internet services. Further, most schedulers are not designed for multi-carrier operation, which makes them unsuitable for multiple carrier—data and voice (MC-DV) environments.
These existing scheduling techniques fail to provide an adaptive scheduling criterion that is capable of evolving to meet the constantly varying demands of the wireless communication environment to optimize throughput while ensuring a defined degree of fairness among users. Accordingly, there is a need for an adaptive scheduling technique to optimize throughput while ensuring fairness among users. There is a further need for a scheduling technique with these capabilities that can optimize multi-carrier diversity in order to maximize overall system throughput while maintaining a desired degree of fairness.